Os trigonum

Case contributed by Dr Mohammad Taghi Niknejad


Work up for heel pain.

Patient Data

Age: 50 years
Gender: Female

Lateral view of the ankle demonstrates a well-corticated bone fragment posterior to the talus. 

Case Discussion

This is consistent with an os trigonum, a common accessory bone found just posterior to the lateral tubercle of the posterior talar process.

The ossicle usually forms between 7-13 years of age and fuses with the talus in a majority of patients by approximately age 17, otherwise persisting as an os trigonum. 

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